The desire for a clean and cared-for appearance is probably as old as man. Bad skin and an uncared-for hair costume offer ideal breeding grounds and homes for pathogens and parasites of all types. The desire for body hygiene was continuously intensified when, in the 1960s, besides the “classical” soap, it was also possible to formulate liquid cleansing compositions with newly developed synthetic surfactants. Since this time, we can no longer imagine daily life without bathing and showering, and a large number of products for cleansing the various parts of the body are nowadays available to the consumers.
Cosmetic and/or dermatological cleansing preparations are generally applied in the form of a foam with water to the parts of the body to be cleansed. The basis of virtually all cosmetic or dermatological cleansing preparations are washing-active surfactants. Surfactants are amphiphilic substances which can dissolve organic, nonpolar substances in water. They are characterized by ambivalent behaviour towards water and lipids: the surfactant molecule comprises at least one hydrophilic group and one lipophilic group which permit the positioning at the interface between these two classes of substance. In this way, surfactants ensure a reduction in the surface tension of the water, wetting of the skin, easier soil removal and dissolution, easy rinsing and—if desired—also foam regulation. The basis for the soil removal of lipid-containing soiling is thus given.
The hydrophilic moieties of a surfactant molecule are mostly polar functional groups, for example —COO−, —OSO32, and —SO3−, whereas the hydrophobic moieties are generally nonpolar hydrocarbon radicals. Surfactants are generally classified according to type and charge of the hydrophilic molecule moiety. In this regard, it is possible to differentiate between four groups:                anionic surfactants,        cationic surfactants,        amphoteric surfactants and        nonionic surfactants.        
Most cosmetic and dermatological cleansing preparations are in the form of liquids of greater or lesser viscosity (cleaning washes, gels, and milks) or in the form of a solid (e.g. soap and washing synthetics). They are generally applied using the hands or fingers to the skin or the skin appendages (e.g. hair, nails).
For the cleaning of keratin fibres and/or skin, use is generally made of shampoos and shower gels and/or face cleansers which comprise surfactants or surfactant mixtures and care substances. Such surfactant-containing cleansing and/or shaving compositions (e.g. shampoos, shower gels, shaving foams, etc.) are subject to a large number of requirements which these preparations should satisfy at the same time: these preparations are expected to be skin-compatible and to leave behind a pleasant feel on the skin following application to the skin. This skin, in particular the epidermis, being a barrier organ of the human organism, is subjected to external effects to a particular degree. Such effects can exert irritation to the skin which, in people with sensitive or injured skin, can lead to reddening, tightness, burning and/or itching. Such effects include UV irradiation, mechanical stresses, and contact with irritative substances. Areas of skin which are subjected to these effects in a largely unprotected way and react sensitively include, in particular, the scalp. Besides the solar irradiation to which the scalp is exposed with greater or lesser protection depending on the hair style, mechanical stresses resulting from combing, brushing, and cutting (including shaving), the scalp is also subjected to contact with irritative substances. Besides chemicals which are used for colouring the hair or permanent waving, mention may be here in particular of the surfactants which are used during often daily hair washing. After hair washing, the hair and/or the scalp is often subjected to further treatments which care for the hair and which are intended to stimulate the scalp, but which likewise lead to the described undesired effects.
The surfactants and surfactant mixtures used are composed of anionic, amphoteric and/or nonionic surfactants. The usual use concentrations of the surfactants up to about 25% and the application conditions customary for body- and hair-cleansing, modern shampoo compositions have good skin compatibility. Nevertheless, in the case of a sensitive scalp or increased use (sportsman), scalp irritations may result. The use of relatively small use concentrations or relatively mild surfactants does not represent a solution to this problem since losses in performance with regard to the foaming ability and the foam creaminess are always also associated with it.
Moreover, the formulations should be easy to foam and form a creamy, finely bubbled foam. However, such preparations as the prior art have the disadvantage that they fulfil these requirements in an only inadequately consistent manner. Good foaming products are generally less skin-friendly and leave behind a dry feel on the skin. Especially mild, skin-friendly products, in turn, generally do not foam well.
A further disadvantage of the prior art consists in the fact that, particularly in industrialized countries, there is an increase amongst the population in incompatibilities and allergic reactions towards a large number of chemicals and ingredients of cosmetics and dermatological compositions. Surfactant-containing cosmetic and dermatological preparations are also being affected by this development to an increasing degree since they can sometimes partly dissolve the protective lipid layer on the skin and, on the one hand, penetrate deep into the skin, on the other hand remain on the skin for a long time. For this reason, the concentration of surfactants in cosmetic and/or dermatological preparations should be kept as low as possible. In addition, there is a need for surfactant-containing preparations with varying surfactant composition since incompatibilities and allergic reactions are substance-specific and the people affected are thus given the option of using cosmetic and/or dermatological preparations with a composition which is matched to their incompatibility profile.